WASHINGTON (CNN) -- Global security experts expressed concern Sunday that Pakistan's nuclear arsenal could wind up in the hands of Islamic radicals after President Gen. Pervez Musharraf last weekend declared a state of emergency.

"Make no mistake: This is a very dangerous situation," said John Bolton, the former U.S. ambassador to the United Nations.

But Bolton told CNN's "Late Edition with Wolf Blitzer" that he would urge the United States to continue to back Musharraf, whose government has received $10 billion in U.S. aid since 2001.

In the 1980s, some of Pakistan's nuclear labs were controlled by Abdul Qadeer Khan considered responsible for leaking technology to Libya, North Korea and Iran. Musharraf announced in 2004 that he had pardoned Khan.

Pakistan's nuclear stockpile may be technically secure, Bolton said but the issue isn't whether the weapons are locked away. "It's a political issue," the former U.S. ambassador said. "If the military comes unstuck, if it divides, then the technical fixes won't protect those weapons." Watch Musharraf say he will hold elections in early 2008 »

Musharraf is in a difficult spot, Bolton said. "Even the military is filled with Islamic fundamentalists that he's tried to keep in lower positions."

"But they're pervasive," he said. "And he doesn't have the flexibility of a real military dictator."

Bolton urged U.S. officials to consider more than whether Pakistan is being ruled democratically. "I'd have to put securing those weapons at the top of our agenda."

Richard Holbrooke, U.S. ambassador to the United Nations under President Clinton, told CNN, "everyone should be concerned about this arsenal ... This is is an extraordinarily volatile situation. We don't want to see Pakistan, with its bombs, fall into the hands of people like [Iranian President Mahmoud] Ahmadinejad and the mullahs."

Sen. Joe Biden, a Democratic presidential candidate, told CNN he considers the matter important but less pressing.

"I'm very concerned about it -- not immediately, but over the next year to two years," the Delaware senator said.

"They have 24 to 55 [nuclear] weapons. They have not only the bomb, the thermonuclear device, they have the missile that can couple with the bomb, and it can fly all the way to the Mediterranean."

But former Deputy Secretary of State Richard Armitage said Pakistan's nuclear weapons are secure, and cautioned against overreacting.

"That nuclear arsenal is, one, dispersed, and second, carefully guarded by the army," he told CNN. "I think -- in the short or even medium term -- should things turn badly, we are not going to worry about nuclear weapons in the first instance."E-mail to a friend